The blue smoke told me it's time for new rings on the Fronty. They have over 50K miles on them, so probably due..
Not only are these an odd .050 over, but the compression rings are thicker(axial height) than modern: 1/8"!
These are about 20 year old Egge pistons - special for Chevy crank and rods in a T. They don't list them anymore, so I don't hold out much hope, but I'll call them manana.
Ford 312 bore is also 3.800, but their rings are narrower..
I found 1/16" rings for 3.800 bore. Could I double up on them?
Short answer: no.
Best way forward: get a new set of pistons after you check the bore carefully with a dial bore guage to be sure it is not worn too much. Modern piston rings are typically 1/16" / 1/16" / 3/16" ring size. Arias and Venolia are both in your area and are reasonable in price, with great service.
If the bore is worn too much then obviously you need to bore it enough to straighten out the walls.
I don't think doubling up cast iron rings will be a good idea but for many years since the late 30's, to allow for a worn bore, steel spring rings have been made to do the job, called Cord or Cord Duaflex rings. They are like the spring ring on the 3 piece oil ring so you fit them in packs, as many as you can fit to replace the compression rings. If available in the US? they are in the united Kingdom.
I have an R755 Jacobs in a biplane.
The pistons have four ring grooves and seven rings in each piston.
All doubled up except the top ring.
Short answer: yes.
I did it in an old International T 20 tractor about fifty years ago, too.
I like Yes. Thanks, Bob.
Rings are stacked all the time.
Remember it's ONLY the bottom ring that's doing the work. The ring above is just taking up space.
Could you use a set of 60 over and file to get the correct gap?